In a production process it is frequently necessary to monitor and control visual characteristics of the surfaces of objects. Such control is necessary to assure that the proper shade of paint or other coating has been applied and that such application is uniform and proper thickness. Monitoring is also necessary to assure that the appropriate surface finish, as for example a gloss or matte finish is present. The necessity of maintaining such control is particularly significant in both the manufacture of objects which are assembled from a variety of separate parts and in the fabrication of objects having large surface areas. In the instances where a number of parts are assembled it is generally desired that visual uniformity of the parts be maintained, and in instances where large objects are being manufactured it is generally necessary to maintain control so as to assure uniformity of color, texture and finish thereacross. The manufacture of automobiles involves both manufacturing modalities and the need for the system disclosed hereinbelow is particularly great in that industry.
The most immediately apparent feature of an automobile is its exterior finish and even minor mismatches or flaws in the paint and finish thereof detract significantly from its appearance. Accordingly, automobile manufacturers carefully monitor the visual characteristics of the paint and finish of automobiles during their manufacture. Such inspection generally is carried on by trained personnel and frequently involves the use of a number of separate, specialized measuring tools. For example, colorimeters may be employed to measure the color value of a painted surface to assure that the paint has the proper hue, saturation and lightness; as well as to assure that differing portions of the automobile have the same color values. Similarly, other measurement tools such as gloss meters or distinctness of image meters may be employed to assure that the proper reflectivity is present in the painted surface.
Heretofore such measurements were expensive, time consuming and difficult to implement in a mass production system. It will be seen then what is needed is an inspection system for monitoring visual characteristics of surfaces, particularly coated surfaces such as painted or plated surfaces, which system is compatible with a mass production process, does not require skilled personnel for operation or interpretation of data produced thereby. Furthermore, such a system should be capable of measuring a variety of surface parameters and be adapted to determine if the coated surface meets a desired group of specifications.
The present invention provides such an inspection system and has utility in mass production processes where it is necessary or desirable to inspect plated, polished, painted or other coated surfaces to assess a plurality of parameters thereof. The system disclosed herein has significant utility in mass production processes for the manufacture of automobiles, aircraft, architectural panels, and the like.